Electrical contact assembly

ABSTRACT

An electrical contact assembly ( 10 ) which includes a probe ( 12 ) and a housing ( 14 ) in which the probe ( 12 ) is selectively receivable at least in part. The probe ( 12 ) has an electrically conductive contact member ( 16 ) for selectively making contact with an electrical cable, contact or the like. The housing ( 14 ) includes a holding formation ( 15 ) defining a holding zone ( 62 ) in which an electrical cable ( 64 ) is receivable. The contact member ( 16 ) is displaceable into an operative position in which it is positioned in the holding zone ( 62 ) to make electrical contact with the cable ( 64 ).

BACKGROUND OF THE INVENTION

THIS INVENTION relates to an electrical contact assembly. It alsorelates to a housing and a probe for use in the assembly.

Testing apparatus such as continuity testers are well known. Suchapparatus may be in the form of a probe having a contact which isselectively located at various points in an electrical circuit tomonitor continuity.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided an electricalcontact assembly, which includes

a probe including an electrically conductive contact member; and

a housing in which the probe is selectively at least partiallyreceivable, the housing including a holding formation defining a holdingzone in which an electrical cable is receivable and the contact memberbeing displaceable into an operative position in which it is positionedin the holding zone to make electrical contact with the cable.

The housing may include an end portion which defines the holdingformation. The end portion may be shaped and dimensioned to facilitatepenetration of a wiring harness thereby to enable a user to locate thecable in the holding formation.

The end portion is typically tapered and defines a hook-like holdingformation.

The holding formation may define a convex abutment surface which definesa terminal end of the holding zone and against which the cable abuts inuse.

The housing may define at least one gripping formation shaped anddimensioned to facilitate gripping of the housing by a user. Typically,the assembly includes two concave gripping formations arranged in asyringe-like fashion. The gripping formations may protrude outwardlyfrom an upper end of the housing.

The housing may include a locking member for locking the contact memberin the operative position. Typically, the locking member is mountedpivotally to allow displacement into an operative position in which itfrictionally engages the probe in such a fashion so as to retain thecontact member in its operative position.

The probe may include a shaped body portion which is at least partiallyreceivable within a complementary socket formation in the housing. Thecontact member may be mounted to a front end of the body portion andextend through the housing towards the holding zone.

The probe may include releasable mounting means for releasably mountingthe contact member to the body portion. The contact member may be in theform of an elongate needle-like member. The releasable mounting means istypically in the form of an internal and external screw thread.

The body portion may include an outer component which is selectivelyreceived within the housing, and an inner component to which the contactmember is mounted, and which is at least partially received within theouter component and displaceable relative to the outer component betweena dormant position and an operative position in which the contact memberis positioned in the holding zone.

The probe may include biassing means for biassing the inner component inits dormant position. The biassing means is typically in the form of acompression spring.

The inner component may define a hollow chamber arranged to receiveelectrical illumination means which has one terminal connectable to thecontact member.

The inner component may be formed from at least a translucent materialthereby to enable a user to monitor illumination of the electricalillumination means.

The housing may include reflection means for reflecting light emitted bythe illumination means to facilitate detection thereof by a user.

The inner component may include a releasable closure member forretaining the illumination means within the hollow chamber.

The assembly may include a flexible lead. connected to another terminalof the illumination means and including a releasable electrical clip forselective connection to an earth line.

Further in accordance with the invention, there is provided a housingfor use in an electrical contact assembly as hereinbefore described, thehousing being arranged selectively and removably at least partially toreceive a probe and the housing including an end portion which defines aholding formation, the end portion being shaped and dimensioned tofacilitate penetration of a wiring harness thereby to enable a user tolocate a cable in the holding formation.

The end portion is typically tapered and defines a hook-like holdingformation.

The holding formation may define a convex abutment surface which definesa terminal end of a holding zone in which the cable is receivable andagainst which surface the cable abuts in use.

The housing may define at least one gripping formation shaped anddimensioned to facilitate gripping of the housing by a user. Typically,the housing defines two concave gripping formations arranged in asyringe-like fashion.

The housing may include a locking member for locking a contact member ofthe probe in an operative position in which it makes electrical contactwith the cable.

The housing may include reflection means for reflecting light emitted byillumination means to facilitate detection thereof by a user.

Further in accordance with the invention, there is provided a probe foruse in an electrical contact assembly as hereinbefore described, theprobe including a body portion which is at least partially receivablewithin a housing, and a contact member mounted to a front end of thebody portion and extending through the housing towards a holding zonedefined by the housing for holding an electrical cable.

The probe may include releasable mounting means for releasably mountingthe contact member to the body portion. The contact member may be in theform of an elongate needle-like member. Typically, the releasablemounting means is in the form of an internal and external screw thread.

The body portion may include an outer component which is selectivelyreceived within the housing and an inner component to which the contactmember is mounted, and which is at least partially received within theouter component and displaceable relative to the outer component betweena dormant position and an operative position in which the contact membermakes electrical contact with an electrical cable in use.

The probe may include biassing means for biassing the inner component inits dormant position. The biassing means is typically in the form of acompression spring.

The inner component may define a hollow chamber arranged to receiveelectrical illumination means which has one terminal connectable to thecontact member.

The inner component is typically formed from a translucent materialthereby to enable a user to monitor illumination of the electricalillumination means in use. In other embodiments, the inner component isformed from a generally transparent plastics material.

The inner component may include a releasable closure member forretaining the illumination means within the hollow chamber.

The probe may include a flexible lead connected to the illuminationmeans in use and a releasable electrical clip for selective connectionto an earth line.

The invention will now be described, by way of example, with referenceto the accompanying diagrammatic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 shows an exploded view of an electrical contact assembly inaccordance with the invention;

FIG. 2 shows a top plan view of the assembly of FIG. 1; and

FIG. 3 shows a side view of the assembly of FIG. 1.

DETAILED DESCRIPTION

Referring to the drawings, reference numeral 10 generally indicates anelectrical contact assembly in accordance with the invention. Theassembly 10 includes a probe 12 which is selectively receivable within ahousing 14. When the probe 12 is removed from the housing 14 it may beused in a conventional manner to test continuity or voltage inelectrical circuits. However, when the probe 12 is received within thehousing 14, the assembly 10 is suitable for maintaining electricalcontact with an electrical cable or the like as described in more detailbelow.

The probe 12 is composite in nature and comprises an electricallyconductive needle-like contact member 16 which is mounted to an innercomponent 20 which is slidingly received within the outer component 18.The inner component 20 includes an attachment protrusion 22 whichextends through an aperture in a front face 28 of the outer component 18for displacement as described in more detail below.

Biassing means in the form of a compression spring 24 is positioned overthe attachment protrusion 22 and its one end abuts a front face 26 ofthe inner component 20, and its other end abuts the front face 28 of theouter component 18. In use, the inner component 20 is displaceablerelative to the outer component 18 between a dormant position in whichthe inner component 20 is urged in the direction of arrow 30 and anoperative position in which the inner component is urged in an oppositedirection thereby to displace the contact member 16 forwardly relativeto the outer component 18.

The inner component 20 is moulded from a synthetic plastics materialwhich is preferably translucent or substantially transparent andincludes a hollow chamber in which illumination means in the form of alight bulb 32 is replaceably located. An electrically conductive contactpin 33 extends through the attachment protrusion 22 and its lower end 34makes electrical contact with the contact member 16 and its upper enddefines a head 36 which makes contact with a terminal 38 of the lightbulb 32 via a compression spring 40. Typically, the contact member 16 isattached to the contact pin 33 by means of releasable mounting meansdefined by an internal and external screw thread arrangement.Accordingly, in the event of the contact member 16 being damaged, it maybe replaced.

A closure member in the form of an internally screw-threaded cap 42 isscrewed onto an externally screw-threaded formation 44 of the innercomponent 20 thereby to retain the light bulb 32 within the hollowchamber. A length of flexible cord 46 is connected to releasableattachment means in the form of a crocodile clip 48 for makingelectrical connection with an earth line, typically an earth line in amotor vehicle. The flexible cord 46 is in electrical contact with aterminal 50 of the light bulb 32 via a contact member 35. The innercomponent 20 is rectangular in cross-sectional outline and is receivedwith clearance within a complementary formation defined in the outercomponent 18. The outer component 18 is also rectangular incross-sectional outline and is shaped to be received within acomplemental socket 52 of the housing 14 with a friction fit.

The housing 14 includes an elongate nose portion 54 which terminates ina holding formation 56. The holding formation 56 is tapered (see FIGS. 2and 3) and arranged to facilitate insertion thereof into a wiringharness.

The housing 14 includes two convex gripping formations 58, 60 (see FIGS.1 and 3) which are shaped and dimensioned to facilitate gripping of thehousing 14 by a user. The housing 14 is typically in the form of aunitary moulding of plastics material and the holding formation 56defines a holding zone 62 (see FIGS. 2 and 3) for selectively holding anelectrical cable 64 which typically forms part of a wiring harness. Aterminal end of the holding zone 62 is defined by a convex abutmentsurface 66 against which the electrical cable 64 abuts in use. Theabutment surface 66 is shaped to facilitate penetration of a needle-likeend 68 of the contact member 16 through a plastics casing of sheath ofthe electrical cable 64 thereby to make electrical contact with a coreof the cable 64.

The outer component 18 of the probe 12 is received within the socket 52with a friction fit and abuts an abutment formation 70 (see FIG. 3)defined by the housing 14. When the probe 12 is received within thehousing 14, relative displacement of the inner component 20 relative tothe outer component 18 by exerting a longitudinal force in the directionof arrow 72 (see FIG. 3) on the cap 42 displaces the needle-like end 68of the contact member 16 from a dormant position (as shown in solidlines in FIG. 3) to an operative position (as shown in broken lines inFIG. 3). In the dormant position, the needle-like end 68 is retractedwithin a body portion 74 of the housing 14 thereby to enable a user toposition the cable 64 in the holding formation 62 in a hook-likefashion. In the operative position, the needle-like end 68 is displacedinto the holding zone 62 to make electrical contact with the cable 64.

In order to retain the contact member 16 in its operative position, alocking arrangement 76 (see FIGS. 1 and 3) is provided. The lockingformation 76 includes a locking lever 78 which is pivoted to thegripping formation 60. The locking lever 78 is pivoted between anoperative position (as shown in FIG. 3) in which it frictionally engagesa friction pad 80 (see FIG. 1) thereby to lock the inner component 20 inits forward position relative to the outer component 18 thereby toretain the needle-like end 68 in its operative position. Reflectionmeans in the form of a convex metal mirror 82 is attached to an innerwall 84 of the gripping formation 58. In use, when the electricalcontact assembly 10 is used, for example, to perform tests on electricalcables located beneath a dashboard of a vehicle, the mirror 82 mayreflect light emitted by the light bulb 32 generally in the directionshown by arrow 86 thereby to facilitate detection thereof by a user.Further, recesses 88, 90 provided in the housing 14 and outer component18 respectively to facilitate viewing of the light bulb 32 by a user.

In use, the assembly 10 is typically used to test power on cables in avehicle as mentioned above. The crocodile clip 48 is then connected to anegative line of the motor vehicle which, in turn, is connected to thelight bulb 32 via the flexible cord 46. The probe 12 may be used as astand-alone unit which may probe various points in an electricalcircuit. In the event of the needle-like end 68 making contact with apositive supply line, the light bulb 32 is illuminated to provide anindication to a user. However, when it is desired fixedly to makecontact with the electrical cable 64, the probe 12 is then insertedwithin the housing 14 and the cable 64 is captured by the holdingformation 56 as shown in FIGS. 2 and 3. The needle-like end 68 may thenbe locked in its operative position in which it permanently makescontact with the electrical cable 64. Further, the capturing of thecable 64 by the assembly 10 is then facilitated by the shape of theholding formation 56.

The Applicant believes that the invention, as illustrated, provides aversatile electrical contact assembly 10 which may be used as astand-alone probe 12 for testing electrical circuits, or the probe 12may be removably inserted within the housing 14 thereby to enable theprobe 12 to make permanent or continuous contact with the electricalcable 64.

I claim:
 1. An electrical contact assembly, which includes an elongateprobe having opposed fore and rear ends, the probe including alongitudinally arranged electrically conductive contact member having apointed fore end which provides the fore end of the probe, and anexternally exposed electrical connecting member electrically connectedto the pointed fore end of the contact member; a housing including abody portion which is electrically non-conductive and which includes anelongate internal socket having opposed, open fore and rear ends, and aholding formation fast with the body portion and arranged to extendbeyond the open fore end of the internal socket and transversely to holdan electrical cable in alignment with the open fore end of the internalsocket, the probe being separate and apart from the housing and beingreplaceably receivable in the internal socket via the open rear end ofthe internal socket, the electrically conductive contact member beingselectively movable relative to the internal socket between a dormantposition of the probe in which the pointed fore end of the electricallyconductive contact member is retracted within the internal socket and anoperative position of the probe in which the pointed fore end projectsfrom the internal socket toward the holding formation.
 2. An electricalcontact assembly as claimed in claim 1 in which the probe includes anouter hollow component which is replaceably, longitudinally, receivablein the internal socket; an inner component which is longitudinallymovable along the outer component, the contact member being fast withthe inner component, and the pointed fore end being forwardly extendablebeyond the outer component, the electrical contact assembly including alocking arrangement arranged selectively to lock the inner component tothe housing with the probe in the operative position and with thepointed fore end projecting from the internal socket toward the holdingformation.
 3. An electrical contact assembly as claimed in claim 2 inwhich the locking arrangement includes a finger operable lever pivotedon the housing, the lever including a finger operable force formationand a load formation arranged to act on the inner component when thelever is operated.
 4. An electrical contact assembly as claimed in claim3 in which the inner component includes a friction pad offered to theload formation for frictional abutment.
 5. An electrical contactassembly as claimed in claim 3 in which the locking arrangement isarranged to lock the inner component selectively in the dormant positionof the probe and in the operative position of the probe.
 6. Anelectrical contact assembly as claimed in claim 2 in which the innercomponent is resiliently biased relative to the outer component to urgethe pointed fore end rearwardly.
 7. An electrical contact assembly asclaimed in claim 2 in which the contact member is replaceable.
 8. Anelectrical contact assembly as claimed in claim 1 in which the probeincludes a replaceable light bulb electrically connected in seriesbetween the contact member and the externally exposed electricalconnecting member.
 9. An electrical contact assembly as claimed in claim8 in which the light bulb is disposed within the inner component, theinner component being translucent.
 10. An electrical contact assembly asclaimed in claim 8 which includes a reflector arranged in use to reflectlight rays from the light bulb to externally of the electrical contactassembly.
 11. An electrical contact assembly as claimed in claim 1 inwhich the probe is replaceably frictionally receivable in the internalsocket.
 12. An electrical contact assembly as claimed in claim 2 inwhich the outer hollow component is frictionally receivable in theinternal socket.